Ignition system for internal-combustion engines



June 19, 1951 c. COLVIN ETAL I 2,557,527

IGNITION SYSTEM FOR INTERNAL-COMBUSTION ENGINES Filed Sept. 23, 1948 C L ol'vin Ez y'ejze 8113329012 1' IN V EN TOR.

Patented June 19 1951 IGNITION SYSTEM FOR INTERNAL- COMBUSTION ENGINES Clifford Colvin, en-a, and Eugene o. Bettoni, Bloomfield Hills, Mich., assignors to George M. Holley and Earl Holley Application September 23, 1948, Serial No. 50,796 1 Claim. ('01. 123117) The object of this invention is to advance and to promptly retard the spark of an automobile engine as circumstances require, specifically to advance:

(a) when the speed increases at wide open throttle.

(b) When the throttle is opened and the engine runs slowly.

(c) To retard the spark to its non-knocking position very quickly when the throttle is opened quickly at low engine speed. (To avoid the well known acceleration knock.)

The figure shows the preferred form of our invention.

In the figure, I0 is the air entrance of a conventional carburetor l2. I4 is the fuel nozzle discharging into the venturi IS in the air entrance of the main air passage II. (There is a low speed fuel outlet discharging into the mixture outlet I9 and discharging adjacent the upstream lip'of the butterfly throttle 32.) i8 is a small passage leading out of the throat of the venturi l6 into a chamber 20. 22 is the first moving wall or diaphragm forming the left hand wall of chamber 20. 24 is a second moving wall or diaphragm forming the left hand wall of a chamber 26 which is connected through a pipe 23 with an opening 30 in the main air passage ll, located just above the atmospheric side of the lip of the carburetor throttle 32 when the carburetor throttle 32 is in its idle position.

A spark control rod 34 engages with plate 44 and is moved by two means:

(a) Directly by the diaphragm 22 to which it is connected positively, and

(b) Indirectly by a sleeve or tube 36 surrounding the rod 34.

This sleeve 36 is slotted so that it can pull the r ght hand end 38 of the rod 34 to the left but the rod 34 is free to be moved to the left by springs 46, 41 and plate 44, even though the tube 36 remains in the position shown. In other words theend of the rod 34, numbered 33, has a one way connection which projects through a slot in the sleeve 36, and engages with the circuit breaker plate 44. The tube 36 has a rod extension 40 which is engaged by a compression spring 42. The spring 42 engages with a stationary abutment on the left and with an adjustable lock-nut 43 threaded onto the rod 40 and forming the movable abutment on the right for the spring 42. The adjustment of nut 43 regulates part throttle spark advance. This spring is designed to cause a rapid movement to the right of the sleeve 36 so as to permit the rapid rotation of the 2 plate 44 (clockwise) to retard the spark whenever the throttle is quickly opened, even if it is not'opened completely. The absence of restrictions in the pipes l3 and 28 ensures the rapid retardation of the spark.

The plate 44 is pulled clockwise by two springs 46 and 41, one of which is initially tight, the other one is loose. These three springs 42-46-41 control the position of the plate 44 at all times. The reason one of the two springs 46-41 is loose is that one thus tightens up before the other. (See Westcott et a1. case,'filed December 20, 1946, Serial No. 717,536, now Patent No.

I to provide a maximum but limited advance of the spark determined by the clearance of the pins 56 and 51 in these openings.

Operation If running normally (approximately 7 pounds per square inch) suction is applied to the second moving wall 24 and the spring" is set to be overcome by this suction at any suction greater than say 1% pounds per square inch. The diaphragm 24 is held in the position shown when the throttle 32 is suddenly opened somewhat beyond the position shown in broken lines. The suction in the mixture outlet I9 in that case drops. Instantly the spring 42 removes the load on the rod end 38. imposed by the second moving wall 24 which held the spark advanced, and as the suction in venturi I6 is still feeble the two springs 46-4| quickly restore the spark to a relatively slot in the tube 36 need not be made much wider than the pin 38 to permit the necessary movement.

What we claim is:

An internal combustion engine ignition system. a main air passage, a throttle therein and a main air entrance therefor, a streamlined restriction in said entrance, a first chamber. a first moving wall therein, a passage from the chamber to the air entrance at said restriction so that the moving wall responds to the pressure drop at said re-.

hold it in its spark retarded position whenever the engine is not running, a second control spring for said second moving wall, a first rod connecting the first moving wall with said plate, a second rod connecting the second moving wall with said plate including a one way connection between the second rod and said plate so that the plate can be advanced by the first.moving wall although the second moving wall is held back by its second control spring, said second control spring having a stillness such that normal engine suction causes it to yield so as to permit the sec- 3" ond moving wall to advance the spark in response to engine suction downstream from said throttle when the engine is running at any normal speed and the throttle is set for normal road load, in which one end of the second rod is slotted to permit one end of the first rod to project through said slot to engage the plate, the other end of the said second slotted rod continuing as a rod which rod is engaged by said second control spring and is threaded and provided'with an adjustable abutment to vary the strength of the engine suction at which the second rod engages with the spark advance circuit breaker plate.

CLIFFORD COLVIN. EUGENE C. BE'I'IONI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'EN'I'S Number Name Date 1,798,726 Chryst et a1 Mar. 31, 1931 1,818,079 Meade Aug. 11, 1931 1,845,818 Spiller Feb. 16,1932 2,091,924 Harmon Aug. 31, 1937 2,470,366 Ostling May 17, 1949 2,503,753 Mallory Apr, 11, 1950 FOREIGN PATENTS Number Country Date 514,206 France Nov. 13, 1920 

